There are two parts of large crustal hydrothermal systems that ultimately relate to exploration for deposits. Distal haloes to mineralisation represent the outer metasomatic zones in which trace elements with broader dispersion patterns than the ore-forming ingredients are added to the host rocks (eg albite-epidote rocks in VHMS systems). Source rocks are zones where metals are leached from the host rocks to potentially form an ore deposit (eg base metal depleted chlorite-quartz rocks in VHMS systems). Such patterns are difficult to recognise where differential exhumation has been insufficient to expose different crustal levels related to the mineral system. This paper uses field and geochemical data, and geochemical modelling, for a Precambrian example in which Cu-Au ore deposits and regionally extensive alteration systems have been differentially exhumed, enabling the linking of potential regional metal sources with the deposits. This study has application to younger rocks in which faulting has exhumed different parts of the total hydrothermal system. CITATION: Oliver, N H S and Cleverley, J S, 2019. Source and transport paths in large hydrothermal systems: mapping and geochemical modelling of albitisation and veins around IOCGs, in Proceedings PACRIM 2019, pp 162164 (The Australasian Institute of Mining and Metallurgy: Melbourne).